Study On The Loss And Retention Of Nitrogen During High Temperature Livestock Manure Composting

The intensive development of China's livestock and poultry breeding industry had entered a period of rapid development.The resulting large amount of livestock and poultry excreta had also brought about greater risks of environmental pollution.High-temperature and aerobic composting was one of the ways of resource utilization of livestock and poultry manure.It can not only achieve the harmless and quantitative reduction of livestock and poultry waste,but also the obtained organic fertilizer can effectively improve the soil fertility.However,during the composting process,the nitrogen in the raw materials easily converted to NH₃,N₂O,and other gases to evaporate,which lead to reduced fertilizer efficiency and serious air pollution.Therefore how to solve the problem of excessive nitrogen loss in compost was of crucial importance.In this study,feces?chicken feces,insect feces?and sawdust were used as raw materials.Based on the study of nitrogen conversion law in high-temperature compost,screening of the impact of iron salts,copper salts,superphosphate,sodium chloride,acetic acid and other nitrogen retention agents And acetic acid bacteria,acetic acid fermentation bacteria,ozone oxidation method on nitrogen conservation effect during compost.Through the addition of complex copper salt?CCS?which mixed alkaline copper carbonate,basic copper phosphate,basic copper phosphate and basic copper nitrateto fix the nitrogen in the composting process,it was found that CCS had a good nitrogen-retaining effect,and the effects of CCS addition?m?,C/N,and moisture content?w?on the nitrogen conservation effect were investigated.Through the orthogonal design,the optimum parameters of the composting process were obtained,and the environmental safety and cost of adding CCS were analyzed.The main results are as follows:?1?During the 4 stages of mesophilic phase,thermophilic phase,cooling phase and mature phase,nitrogen loss mainly occurred at the mesophilic and thermophilic phase,in the form of ammonium nitrogen converted to NH₃ volatilization,so the ammonium nitrogen content fluctuated greatly.Nitrate nitrogen began to form in the cooling phase,and there were differences in the morphological trends of the two nitrogen species in different C/N.Therefore,the key period for nitrogen fixation should be during the mesophilic phase and thermophilic phase.?2?The total nitrogen loss rate?T?of CCS was 12.08±0.86%,and the total nitrogen loss reduction rate?L?was 62.93±0.99%.Compared with the control group,CCS had obvious nitrogen-retention effect.?3?CCS addition?m?had a significant effect on nitrogen loss rate?P<0.05?,and the effect of C/N was not significant?P>0.05?.Therefore,the order of impact of three factors on nitrogen loss and reduction was m>C/N>water content?w?.?4?The optimal combination of experimental conditions is:m=1.4 wt%,initial C/N=20,w=60 wt%,under which conditions L?%?=62.19±1.98.Seed germination rate?GI?was more than 80%,mean that organic manure was completely maturity and non-toxic to plants.?5?When organic fertilizers treated with CCS were applied to the soil,the Cu²⁺content was within the limit of environmental quality standards for soils of China,which was harmless to the environment and had a low cost,and could be popularized and used.The innovation of this study:the first use of composite copper salt?CCS?treatment of compost raw materials,nitrogen conservation effect is obvious.and determined that the best nitrogen conservation effect was achieved with a CCS addition rate of 1.4 wt%,a C/N ratio of 20,and a water content of 60%.,the total nitrogen loss rate was62.19±1.98%.Adding CCS not only had good nitrogen conservation effect,but also had low cost,safe usage and good application prospects.